Zhou Dan, You Wen, Yang Fei, Chen Rui, Xu Haitao, Tong Yongfen, Hu Bin, Hu Lin, Xie Yu, Chen Lie
Key Laboratory of Jiangxi Province for Persistent Pollutants, Control and Resources Recycle, Nanchang Hangkong University, 696 Fenghe South Avenue, Nanchang 330063, China.
Institute of Polymers and Energy Chemistry (IPEC), Nanchang University, 999 Xuefu Avenue, Nanchang 330031, China.
ACS Appl Mater Interfaces. 2021 Oct 27;13(42):50187-50196. doi: 10.1021/acsami.1c13394. Epub 2021 Oct 15.
The electron transport layer (ETL) exerts a dramatic influence on the power conversion efficiency (PCE) of the nonfullerene organic solar cells (NOSCs). Currently, the majority of the organic ETLs possess a relatively poor conductivity, which is not conducive to carrier transport and collection. Herein, we design and develop a novel hyperbranched conjugated polyelectrolyte (CPE) based on n-type perylene diimide (PDI) as the center core and quaternary ammonium salt as the side polar groups. The lone pair electrons of the nitrogen atoms can transfer to the electron deficient PDI core and endow the molecule with an efficient n-type self-doping effect. Moreover, the hyperbranched structure makes the molecule functionalized with more side polar groups, favoring forming more dipoles and stronger dipole moments. Therefore, the CPE PTPAPDINO possesses a high conductivity and can notably decrease the work function (WF) of the electrode, contributing to the carrier transport and collection of the device. The NOSC with PTPAPDINO as ETL delivers an excellent PCE of 15.62%, which is even superior to the device using the classical PDINO ETL. Moreover, the PCE can retain 82.6% of the optimal device when the thickness has been increased to 28 nm. These results manifest that it is a feasible strategy to design an n-type self-doping hyperbranched CPE as efficient ETL, and PTPAPDINO is a promising alternative ETL for high performance NOSCs.
电子传输层（ETL）对非富勒烯有机太阳能电池（NOSCs）的功率转换效率（PCE）有着显著影响。目前，大多数有机ETL的导电性相对较差，这不利于载流子的传输和收集。在此，我们设计并开发了一种新型的超支化共轭聚电解质（CPE），它以n型苝二酰亚胺（PDI）为中心核，季铵盐为侧基极性基团。氮原子的孤对电子可以转移到缺电子的PDI核上，赋予分子高效的n型自掺杂效应。此外，超支化结构使分子带有更多的侧基极性基团，有利于形成更多的偶极子和更强的偶极矩。因此，CPE PTPAPDINO具有高导电性，能够显著降低电极的功函数（WF），有助于器件的载流子传输和收集。以PTPAPDINO作为ETL的NOSC具有15.62%的优异PCE，甚至优于使用经典PDINO ETL的器件。此外，当厚度增加到28 nm时，PCE仍能保持最佳器件的82.6%。这些结果表明，设计一种n型自掺杂超支化CPE作为高效ETL是一种可行的策略，并且PTPAPDINO是用于高性能NOSCs的一种有前途的替代ETL。
